I tried computing a product of two integers below 2^98256
with MPFUN f77-ieee version 2001-08-02
on thoth on 2002.02.24.
(More precisely: each integer was 16777215^4095, around 2^98280.)
MPFUN took about 74 million cycles.

There is also an MPFUN f90-ieee version 2001-08-02.
The documentation says that MPFUN was made several times faster
at some point;
perhaps this applies to f90-ieee and not f77-ieee.
Anyway, I have no intention of looking for a Fortran 90 compiler.